【正文】 system is inevitable line. The most mon design is the use of ultrasonic distance measurement method to design a microcontroller based car reversing radar system. The design is mainly based on AT89C51 microcontroller features and advantages of the use of ultrasound, ultrasonic ranging system and AT89C51 microcontroller bined in one design a car based on AT89C51 microcontroller reversing radar system. The system uses software and hardware bination of methods. The paper outlines the design of the development of ultrasonic testing and the basic principles expounded the principle and characteristics of ultrasonic sensors. In the ultrasonic ranging system functions and AT89C51 monolithic application, based on the overall position of the system proposed, each of the design elements of the system were introduced the principle and hardware circuit for each unit posed of the main ponents of a detailed description and choices. The paper also describes the design of system software architecture, and is programmed to implement system functions and requirements. Keywords: car reversing radar, AT89C51, ultrasound, measuring distance, LED digital tube 基于單片機(jī)的汽車倒車?yán)走_(dá)系統(tǒng)設(shè)計(jì) 成都工業(yè)學(xué)院 2020 屆 畢業(yè)設(shè)計(jì)（論文） iii 目錄 第一章 緒論 .................................................................................................................... 1 概述 .................................................................................................................... 1 設(shè)計(jì)目的及意義 ................................................................................................... 1 測(cè)距方式的分析與比較 ........................................................................................ 2 第二章 超聲波的發(fā)展及測(cè)距原理 ..................................................................................... 4 超聲波的發(fā)展與運(yùn)用 ............................................................................................ 4 超聲波測(cè)距原理 ................................................................................................... 4 超聲波測(cè)距在汽車上的運(yùn)用 ................................................................................ 6 超聲波傳感器的介紹 ........................................................................................... 7 超聲波傳感器介紹 ..................................................................................... 7 超聲波傳感器的特性 ................................................................................. 8 第三章 系統(tǒng)硬件設(shè)計(jì) ................................................................................................... 10 系統(tǒng)設(shè)計(jì)的要求 ................................................................................................ 10 系統(tǒng)整體設(shè)計(jì)方案 ............................................................................................ 10 單片機(jī)系統(tǒng)介紹 ................................................................................................ 11 AT89C51 單片機(jī)介紹 ................................................................................. 11 .................................................................................... 15 .................................................................................... 16 單片機(jī)的電源電路 ................................................................................... 17 超聲波發(fā)射電路 ................................................................................................ 23 超聲波接收電路 ................................................................................................ 25 CX20206A 集成電路介紹 ........................................................................... 25 ....................................................................................... 26 距離顯示電路 ................................................................................................... 27 報(bào)警電路 .......................................................................................................... 28 音頻集成功放 LM386簡(jiǎn)介 ....................................................................... 28 報(bào)警電路的設(shè)計(jì) ...................................................................................... 30 第四章 系統(tǒng)軟件設(shè)計(jì) .................................................................................................... 30 系統(tǒng)軟件設(shè)計(jì)的框圖 ......................................................................................... 30 系統(tǒng)程序流程圖 ................................................................................................. 31 超聲波發(fā)生子程序和超聲波接收中斷程 .............................................................. 32 超聲波測(cè)距儀的算法設(shè) 計(jì) ................................................................................... 34 顯示程序 ........................................................................................................... 35 報(bào)警程序 ........................................................................................................... 36 結(jié)論 ............................................................................................................................... 37 致謝 ............................................................................................................................... 38 參考文獻(xiàn) ........................................................................................................................ 39 附錄 ............................................................................................................................... 40 附錄一：系統(tǒng)電路圖 ............................................................................................... 40 附錄二：主要元器件清單 ........................................................................................ 41 附錄三：源程序 ...................................................................................................... 42 基于單片機(jī)的汽車倒車?yán)走_(dá)系統(tǒng)設(shè)計(jì) 成都工業(yè)學(xué)院 2020 屆 畢業(yè)設(shè)計(jì)（論文） 1 第一章 緒論 概述 汽車倒車?yán)走_(dá)全稱叫“汽車倒車防撞雷達(dá)”，也叫“汽車泊車輔助裝置”，是汽車泊車或者倒車時(shí)的安全輔助裝置，由